Here is a simple way to set, retrieve and delete cookies from within a Silverlight application.

Click here to open below source code (Cookies.cs)

/// <summary>

/// sets a persistent cookie with huge expiration date

/// </summary>

/// <param name="key">the cookie key</param>

/// <param name="value">the cookie value</param>

private static void SetCookie(string key, string value)

{

    string oldCookie = HtmlPage.Document.GetProperty("cookie") as String;

    DateTime expiration = DateTime.UtcNow + TimeSpan.FromDays(2000);

    string cookie = String.Format("{0}={1};expires={2}", key, value, expiration.ToString("R"));

    HtmlPage.Document.SetProperty("cookie", cookie);

}

/// <summary>

/// Retrieves an existing cookie

/// </summary>

/// <param name="key">cookie key</param>

/// <returns>null if the cookie does not exist, otherwise the cookie value</returns>

private static string GetCookie(string key)

{

    string[] cookies = HtmlPage.Document.Cookies.Split(';');

    key += '=';

    foreach (string cookie in cookies)

    {

        string cookieStr = cookie.Trim();

        if (cookieStr.StartsWith(key, StringComparison.OrdinalIgnoreCase))

        {

            string[] vals = cookieStr.Split('=');

            if (vals.Length >= 2)

            {

                return vals[1];

            }

            return string.Empty;

        }

    }

    return null;

}

/// <summary>

/// Deletes a specified cookie by setting its value to empty and expiration to -1 days

/// </summary>

/// <param name="key">the cookie key to delete</param>

private static void DeleteCookie(string key)

{

    string oldCookie = HtmlPage.Document.GetProperty("cookie") as String;

    DateTime expiration = DateTime.UtcNow - TimeSpan.FromDays(1);

    string cookie = String.Format("{0}=;expires={1}", key, expiration.ToString("R"));

    HtmlPage.Document.SetProperty("cookie", cookie);

}